Primitive Archer

Main Discussion Area => Bows => Topic started by: Maxspin on February 02, 2013, 02:15:52 pm

Title: Hickory backed Lemonwood
Post by: Maxspin on February 02, 2013, 02:15:52 pm
This is a Hickory backed Lemonwood. I glued in a couple of inches of reflex.
I did the dry run and everything looked good. I used TBII for the glue up. Everything looked good after I got all the clamps on it. But…….
After it dried I noticed that the hickory backing had curled up leaving a gap along the edge. I know that Tight Bond is not gap filling. I am afraid that this is a fatal flaw.
I cut the profile on the band saw and took the end pieces inside to break up as kindling. The wood broke before the glue line even with some gap, so there may still be some hope.
I plan to continue working this as a learning experience.
Any recommendations as a gap filler?
(http://i779.photobucket.com/albums/yy71/maxspin_photos/HBL/IMG_2509_zpsfec9db4f.jpg)

(http://i779.photobucket.com/albums/yy71/maxspin_photos/HBL/IMG_2501_zpsb85e34ba.jpg)

After taking it down to the planned periphery line I still have a little gap showing.

(http://i779.photobucket.com/albums/yy71/maxspin_photos/HBL/IMG_2508_zps4a9331a8.jpg)

Things I think I learned.
1.   Cut the profile (close) before glue up. Less material to curl
2.   Offset clamps to the edges each clamp
3.   Work faster or cooler. I was working in the house & the wood burning stove had the house too hot. The glue set up much faster than I expected.
4.   Unibond800 not TBII

Keith
Title: Re: Hickory backed Lemonwood
Post by: Pat B on February 02, 2013, 02:36:50 pm
Since you used TB glue you can remove the hickory backing, clean up the glue surfaces and reglue the backing back down. TB glues will release at 150deg (F). Use a heat gun and starting at one end heat the hickory backing until the heat gets through to the glue. Then work a screw driver or chisel between the backing and belly and start to pry it up. As it comes up move down the limb with the heat until you get to the handle. Then start at the other end and do the same.
  I had to remove a hickory backing so I called the TB folks and asked how. They told me about heating it to make it release. I've used this on a few bows now and it worked great every time.
  Are you using a pressure strip over the backing when you glue it down. This will help prevent the backing from curling.
Title: Re: Hickory backed Lemonwood
Post by: Maxspin on February 02, 2013, 02:47:15 pm
Thanks Pat, I'll heat it up and remove the backing.

5. Use a pressure strip over the backing.  :)

Keith
Title: Re: Hickory backed Lemonwood
Post by: hedgeapple on February 02, 2013, 03:00:53 pm
Max, I would follow PatB's suggestion to the LETTER.  Points to note:
1 work slowly heat then pry a small area then heat another area.  Move slowly, don't get in a rush to pop the hickory off.
2 work one to to the handle AND THEN work the other limb from tip to handle.

I pulled a chunk out off a piece of osage while trying to remove the backing by not following those two key steps.
Title: Re: Hickory backed Lemonwood
Post by: Maxspin on February 02, 2013, 03:14:35 pm
Thanks Dave,
I am feeling much better about this. I was real bummed when I saw that gap.
Can’t wait to get home from work today and start SLOWLY pulling that backing off.

Keith
Title: Re: Hickory backed Lemonwood
Post by: Maxspin on February 03, 2013, 11:09:09 am
I got half of it off last night. That backing is coming off looking like a potato chip. Not sure if it will be salvageable or not.

Got a little frustrated with it so I put it down and worked on a VM for a little while.

(http://i779.photobucket.com/albums/yy71/maxspin_photos/HBL/IMG_2513_zps3f341516.jpg)

(http://i779.photobucket.com/albums/yy71/maxspin_photos/HBL/009ddc58-c746-4aac-818c-63ff955c0a68_zps64fa02a5.jpg)
Title: Re: Hickory backed Lemonwood
Post by: Pat B on February 03, 2013, 12:05:07 pm
Don't worry about it curling up. You can flatten it again with a little heat and clamps but if you are going to glue the bow back up in reflex It won't be a problem if it is curled a little.
 You may also need to put clamps along both sides of the glue-up to prevent the backing from possible curling up along the edges again.